Dog's nose: origin of acquired depigmentation and nose problems

My dog's nose is getting depigmented, why ? Does he suffer from a dietary deficiency?

A) Nose depigmentation, only one symptom observed

It is the most difficult case to explain : let's see different possible hypothesis.

1) Vitiligo

Inherited disease, but not present at birth : it usually appears by the age of 2 years old. It is the "pink nose" syndrom, that is mostly ssen in followin breeds : German Shepherd, German Pointer, Belgian Shepherd, Newfoundland, Doberman, Rottweiler, Bobtail ...

Mechanism : lack of pigment (melanin ), due to a non-explained destruction of the melanin-forming cells (melanocytes).

The evolution is extremely variable : the depigmentation can lay over the whole nose, or disappear. Usually, the lesions do not become ulcerated, except in case of prolonged exposition to the sun.

2) Discoïd lupus

Autoimmune disease, rather frequent in dogs : it is the only one autoimmune disease who does not exhibit any other clinical sign. It occurs mainly between 3 and 8 years old ; predisposed breeds are German Shepherd and Colley.

The most frequent case however, remains incomplete and/or cyclic depigmentation that occurs in adult dogs with black nose: unhappily, the origin is still unknown.
All these hypothesis can be confirmed through histologic examinations : depigmented nose-tissue has to be sampled (biopsy) and microscopically observed.

There is not much to do in those cases : the most important thing is to protect depigmented areas from the sun with protective creams ("total screen"), when sun radiations are specially aggressive.

In case of persistent lesion on the nose, a veterinary examination is necessary. All these affections can be diagnosed by collecting the case history, clinical examination, and complementary examinations (biopsy, serology, mycology).

On a nutritional aspect, pigmentation mechanism requires the following nutrients :

amino-acids : tyrosine, tryptophane

trace-elements : iron, copper

vitamins : folic acid, pantothenic acid.

ROYAL CANIN products contain a large amount of these nutrients and no deficiency is to fear. On the contrary, secondary copper deficiency has been described in dogs who received zinc in excess : the ratio zinc : copper must stay under 10 : 1, even if zinc supplementation is distributed.

Even if sometimes, pigmentation comes back after a change of food, it does not mean anything : depigmentation is a cyclic phenomenon, likely to appear and disappear at any time.